Information recording medium which records information that pertains to integrity

ABSTRACT

An information recording medium of this invention has a plurality of sector fields that record data, and each sector field has an identification information area (recording type area). The identification information area records one of first identification information indicating that data recorded in the sector field has high integrity, and second identification information indicating that data has low integrity.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is based upon and claims the benefit of priority fromthe prior Japanese Patent Application No. 11-318821, filed Nov. 9, 1999,the entire contents of which are incorporated herein by reference.

BACKGROUND OF THE INVENTION

The present invention relates to an information recording medium whichhas a plurality of sector fields that record data, and in which a blockis defined by a set of a predetermined number of sector fields, forexample, a DVD (Digital Versatile Disk). The present invention alsorelates to an information recording apparatus and method for recordinginformation on the information recording medium. Furthermore, thepresent invention relates to an information reproduction apparatus andmethod for reproducing information from the information recordingmedium.

In recent years, information recording media such as a DVD that featureshigh-density recording have been extensively studied and developed. Suchinformation recording medium has a plurality of sector fields whichrecord data, and an ECC (Error Correction Code) block is defined by aset of a predetermined number of sector fields.

Even when data is recorded on some sector fields of such informationrecording medium, the entire ECC block which includes target sectorfields as a recording destination is read. Of the read ECC block data,target data patches a portion corresponding to the target sector fields,and the ECC block is re-arranged and recorded in the original ECC block.Such recording in units of sector fields is called read-modify-write.

Such read-modify-write is suitable for recording PC data that does notrequire real-time processes but is not suitable for recording AV datathat places an importance on real-time processes since it is relativelytime-consuming. In order to avoid read-modify-write, data can berecorded in units of ECC blocks.

Upon recording AV data, in general, initial defect management thatregisters initial defects by format and certify is not made. That is,defects remain on the recording space. Upon recording AV data, it isimportant to continue recording without any interruption ignoring someerrors (defects) in sector fields as a recording destination.

However, when both PC and AV data are recorded on a single informationrecording medium, especially, when PC data is overwritten on AV data,the error rate increases upon read-modify-write due to the absence ofdefect management. That is, ECC block data cannot be read out uponread-modify-write, that ECC block consequently cannot undergo areplacement process, and read-modify-write terminates abnormally.

BRIEF SUMMARY OF THE INVENTION

The present invention has been made to solve the aforementionedproblems, and has as its object to provide the following informationrecording medium, information recording apparatus, information recordingmethod, information reproduction apparatus, and information reproductionmethod:

(1) an information recording medium which can reduce the error rate uponread-modify-write when data is overwritten in units of sector fields ondata recorded in units of ECC block data;

(2) an information recording apparatus and method which can reduce theerror rate upon read-modify-write when data is overwritten in units ofsector fields on data recorded in units of ECC block data; and

(3) an information reproduction apparatus and method which can reducethe error rate upon read-modify-write when data is overwritten in unitsof sector fields on data recorded in units of ECC block data.

In order to solve the above problems and to achieve the above object,the information recording medium, information recording apparatus,information recording method, information reproduction apparatus, andinformation reproduction method according to the present invention havethe following arrangements.

(1) An information recording medium of the present invention is aninformation recording medium which has a plurality of sector fields thatrecord data, and in which a block is defined by a set of a predeterminedof sector fields,

wherein each sector field has an identification information area forstoring one of first identification information indicating that data isrecorded with a first integrity level, and second identificationinformation indicating that data is recorded with a second integritylevel lower than the first integrity level.

(2) An information recording apparatus of the present invention is aninformation recording apparatus for recording information on aninformation recording medium which has a plurality of sector fields thatrecord data and respectively have identification information areas, andin which a block is defined by a set of a predetermined of sectorfields, comprising:

recording means for recording, in the identification information area,first identification information indicating that data is recorded with afirst integrity level when desired information is recorded with thefirst integrity level on the information recording medium, andrecording, in the identification information area, second identificationinformation indicating that data is recorded with a second integritylevel when desired information is recorded with the second integritylevel on the information recording medium.

(3) An information recording method of the present invention comprises:

the step of, when desired information is recorded with a first integritylevel in an information recording medium which has a plurality of sectorfields that record data and respectively have identification informationareas, and in which a block is defined by a set of a predetermined ofsector fields, recording data in each identification information areawith the first integrity level; and

the step of, when desired information is recorded with a secondintegrity level in the information recording medium, recording data ineach identification information area with the second integrity level.

(4) An information reproduction apparatus of the present invention is aninformation reproduction apparatus for reproducing information from aninformation recording medium which has a plurality of sector fields thatrecord data, and in which each sector field has an identificationinformation area that records one of first identification informationindicating that data is recorded with a first integrity level, andsecond identification information indicating that data is recorded witha second integrity level lower than the first integrity level, and ablock is defined by a set of a predetermined number of sector fields,comprising:

reproduction means for acquiring information that pertains to integrityby reproducing the first identification information or secondidentification information from the identification information area.

(5) An information reproduction method of the present invention is aninformation reproduction method for reproducing information from aninformation recording medium which has a plurality of sector fields thatrecord data, and in which each sector field has an identificationinformation area that records one of first identification informationindicating that data is recorded with a first integrity level, andsecond identification information indicating that data is recorded witha second integrity level lower than the first integrity level, and ablock is defined by a set of a predetermined number of sector fields,comprising:

the step of acquiring information that pertains to integrity byreproducing the first identification information or secondidentification information from the identification information area.

Additional objects and advantages of the invention will be set forth inthe description which follows, and in part will be obvious from thedescription, or may be learned by practice of the invention. The objectsand advantages of the invention may be realized and obtained by means ofthe instrumentalities and combinations particularly pointed outhereinafter.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING

The accompanying drawings, which are incorporated in and constitute apart of the specification, illustrate presently preferred embodiments ofthe invention, and together with the general description given above andthe detailed description of the preferred embodiments given below, serveto explain the principles of the invention.

FIG. 1 is a plan view showing the layout of a lead-in area, data area,lead-out area, and the like on an optical disk;

FIG. 2 is a schematic view showing the structure of ECC block datarecorded on the optical disk shown in FIG. 1;

FIG. 3 is a schematic view showing the data structure of sector datagenerated from the ECC block data shown in FIG. 2;

FIG. 4 is a schematic view showing the data structure of a data unitcontained in the sector data shown in FIG. 3;

FIGS. 5A and 5B are schematic views showing the data structure of thedata ID contained in the data unit shown in FIG. 4;

FIG. 6 is a schematic block diagram showing the arrangement of anoptical disk recording/reproduction system according to the presentinvention;

FIG. 7 shows the recording process of PC data and AV data whilediscriminating them depending on write commands;

FIG. 8 is a flow chart showing the process for recording an integrityflag based on a write command;

FIG. 9 is a flow chart showing details of recording in the flow chartshown in FIG. 8, and especially, recording of data smaller than an ECCblock size;

FIG. 10 shows a list of items that pertain to data having first andsecond integrity levels; and

FIG. 11 shows the relationship between the integrity level of data to berecorded and an integrity bit of a block as a recording destination.

DETAILED DESCRIPTION OF THE INVENTION

A preferred embodiment of the present invention will be describedhereinafter with reference to the accompanying drawings.

An example of an optical disk (DVD-RAM disk) as an information recordingmedium according to the present invention will be explained first withreference to FIG. 1.

FIG. 1 shows the layout of a lead-in area, data area, lead-out area, andthe like on an optical disk.

As shown in FIG. 1, an optical disk 1 has a lead-in area A1, data areaA2, and lead-out area A3 in turn from the inner periphery side. Thelead-in area A1 includes an emboss data zone, mirror zone (non-recordingzone), and rewritable data zone. The data area A2 includes a rewritabledata zone which is made up of a plurality of zones, i.e., zones 0 to N.The lead-out area A3 includes a rewritable data zone.

The emboss data zone of the lead-in area A1 records reference signal andcontrol data as an emboss pattern in the manufacture of the optical disk1. The rewritable data zone of the lead-in area A1 recordsidentification data indicating the type of disk, defect management datafor managing a defective area, and the like. Note that the area wherethe defect management data is recorded will be referred to as a DMA(Defect Management Area) hereinafter. The rewritable data zone of thelead-out area A3 records the same data as those recorded on therewritable data zone of the lead-in area A1.

The emboss data zone assured on the lead-in area A1 is comprised of aplurality of tracks, and each track is made up of a plurality of sectorfields. This zone is processed at a predetermined rotational speed.

Zone 0 in the rewritable data zones assured on the lead-in area A1 anddata area A2 consists of X tracks, each of which is made up of Y sectorfields. This zone is processed at rotational speed Z0 (Hz).

Zone 1 of the rewritable data zone assured on the data area A2 consistsof X tracks, each of which is made up of (Y+1) sector fields. This zoneis processed at rotational speed Z1 (Hz) (Z0>Z1).

Zone 2 of the rewritable data zone assured on the data area A2 consistsof X tracks, each of which is made up of (Y+2) sector fields. This zoneis processed at rotational speed Z2 (Hz) (Z1>Z2).

Each of zones 3 to N of the rewritable data zone assured on the dataarea A2 consists of x tracks. Each track of zone 3 is made up of (Y+3)sector fields, and each track of zone 4 is made up of (Y+4) sectorfields. That is, each track of zone N is made up of (Y+N) sector fields.Zone 3 is processed at rotational speed Z3 (Hz) (Z2>Z3), and zone 4 isprocessed at rotational speed Z4 (Hz) (Z3>Z4). That is, zone N isprocessed at rotational speed ZN (Hz) (Z(N−1)>ZN).

The rewritable data zone assured on the lead-out area A3 consists of aplurality of tracks, each of which is made up of (Y+N) sector fields.This zone is processed at rotational speed ZN (Hz).

As mentioned above, the number of sector fields per track increases andthe rotational speed lowers accordingly in turn from zones on the innerperiphery side of the optical disk 1. That is, the optical disk 1 iscontrolled by a ZCLV (Zone Constant Linear Velocity) scheme.

The structures of data recorded on and reproduced from a DVD-RAM will beexplained below with reference to FIGS. 2 and 3. FIG. 2 schematicallyshows the structure of ECC block data. FIG. 3 schematically shows thedata structure of sector data recorded on a recording field.

On each zone of the DVD-RAM, tracks that record data are formed, and aplurality of sector fields which records data of a predetermined unitare formed on each track. One sector field contains a header field andrecording field. The header field records in advance data such asaddresses and the like as an emboss pattern data, and the recordingfield records user data by phase change recording. Also, the DVD-RAMrecords data in a format called ECC block data. Strictly speaking, 16sector data generated from the ECC block data are distributed andrecorded in 16 sector fields. More specifically, one sector data isrecorded on the recording field of one sector field.

As shown in FIG. 2, the ECC block data is comprised of a data block (DB)containing user data, horizontal error correction code (ECC1) andvertical error correction code (ECC2).

The DB is made up of data which line up along predetermined numbers ofrows and columns, and can be broken up into 16 data units (DU). Morespecifically, the DB consists of 172 (bytes)×12 (rows that form theDU)×16 (DUs that form the DB) data. Each DU is made up of 172 (bytes)×12(rows that form the DU) data, and includes 4-byte data ID, 2-byte dataID error detection code (IED), CPR_MAI, 2,048-byte user data, errordetection code (EDC), and the like. The data ID is used to scramble theuser data included in the DU. The IED detects any error in a total of 6bytes including the data ID and this IED. The EDC is used to detect anyerror included in a group of some data in the DU.

The ECC1 is used to correct any errors included in data in the DB in therow direction (horizontal direction). More specifically, the ECC1 ismade up of 10 (bytes)×12 (rows that form the DU)×16 (DUs that form theDB) data.

The ECC2 is used to correct any errors included in data in the DB in thecolumn direction (vertical direction). More specifically, the ECC2 ismade up of {172 (bytes)+10 (bytes)}×16 (DUs that form the DB) data.

Subsequently, sector data will be described below with reference to FIG.3.

Sixteen sector data are generated from one ECC block data. One sectordata is made up of a DU and some data of the ECC1 and ECC2 assigned tothat DU. More specifically, each sector data is made up of {172(bytes)+10 (bytes)}×12 (rows that form the DU)+1 (one row of the ECC2)data.

Note that the data ID and IED contained in the DU of the ECC block datacan be independently read out even when error correction cannot be doneusing the ECC1 and ECC2.

The DU will be explained below with reference to FIG. 4.

As described above, the DU is made of 172 (bytes)×12 (rows that form theDU) data, and includes the data ID, IED, CPR_MAI, 2,048-byte user data,EDC, and the like. More specifically, the start row, i.e., the first rowincludes 4-byte data ID, 2-byte IED, 6-byte CPR_MAI, and 160-byte userdata. Each of the second to 11th rows includes 172-byte user data. Thelast row, i.e., the 12th row includes 168-byte user data and 4-byte EDC.

The data ID will be explained below with reference to FIG. 5A.

The data ID includes data such as 1-byte sector information, 3-byte datafield number, and the like. The sector information includes data such as1-bit sector format type, 1-bit tracking method, 1-bit reflectivity,1-bit integrity flag, 2-bit area type, 1-bit data type, 1-bit layernumber, and the like. An area where the integrity flag is recorded willbe referred to as an integrity flag area hereinafter.

In the sector format type, bit 0 indicates a CLV format, and bit 1 azone format. In the tracking method, bit 0 indicates a pit, and bit 1 agroove. In the reflectivity, bit 0 indicates less than 40%, and bit 140% or higher. In the integrity flag area, bit 1 (first identificationinformation) indicates a first integrity level (high integrity), and bit0 (second identification information) a second integrity level (lowintegrity) lower than the first integrity level. In the type area, bit00 indicates data, bit 01 lead-in, bit 10 lead-out, and bit 11 middle.In the layer number, bit 0 indicates layer 0, and bit 1 layer 1.

Alternatively, the structure of the data ID can be expressed, as shownin FIG. 5B. That is, the data ID includes data such as 1-byte data fieldinformation, 3-byte data field number, and the like. Furthermore, thedata field information includes data such as 1-bit sector format type,1-bit tracking method, 1-bit reflectivity, 1-bit recording type, 2-bitarea type, 1-bit data type, 1-bit layer number, and the like. An areawhere the recording type is recorded will be referred to as a recordingtype area hereinafter.

In the recording type area, bit 0 (first identification information)indicates first integrity level (high integrity), and bit 1 (secondidentification information) second integrity level (low integrity) lowerthan the first integrity level.

That is, bit 1 may indicate the first integrity level and bit 0 mayindicate the second integrity level, as shown in FIG. 5A, or bit 0 mayindicate the first integrity level and bit 1 may indicate the secondintegrity level, as shown in FIG. 5B. That is, the integrity flag shownin FIG. 5A corresponds to the recording type shown in FIG. 5B, althoughthey have different expressions (the roles of bits 1 and 0 arereversed).

Data recorded with the first integrity level is called General data, anddata recorded with the second integrity level is called Real-time-data.General data includes, for example, PC data. Real-time-data includes,for example, AV data. General data and Real-time-data are defined asfollows.

General data: Linear replacement algorithm is applied to a Blockcontaining the corresponding sector if the Block is defective.

Real-time data: Linear replacement algorithm is not applied to a Blockcontaining the corresponding sector even if the Block is defective.

The Linear replacement algorithm will be briefly explained below. TheLinear replacement algorithm is applied upon recording, e.g., PC data.When target data is recorded in a given target block, the recorded datais read out from that target block, and it is confirmed if the targetdata is accurately recorded. As a result of this confirmation, if it isdetermined that the target block is defective and data cannot beaccurately recorded in the target block, recording in the target blockis canceled. Instead, the target data is recorded in a predeterminedblock in another area prepared in advance, i.e., so-called replacementarea. That is, data to be recorded in the target block is recorded inthe predetermined block in the replacement area. Such replacementprocess is the Linear replacement algorithm.

When the linear replacement algorithm is applied to a defective Blockduring write operation, Recording type bit of all the sectors within allBlocks to be written to shall be set to 0b. When Streaming data iswritten to a Block, a defect management scheme other than the linearreplacement algorithm is applied and all the sectors within the Blockshall be written with Recording type bit of 1b. When writing somesectors of a Block, and if the Block is uncorrectable before writing andthe previously recorded Recording Type bits in the Block are recognizedas 1b, then the partially corrected data or padding data of 0b for allbits may be used for the writing data of the other sectors of the Block.A Block with Recording type of 1b shall not be replaced, even if theBlock to be read is found to be defective.

The aforementioned integrity flag will be explained in detail below.Note that the integrity flag is substantially the same as the recordingtype, as described above. Therefore, the following description can beinterpreted as that of the recording type by reading bit 1 as bit 0, andvice versa.

When bit 1 is recorded as the integrity flag in the integrity flag area,a sector field including this integrity flag is included in a blockrecorded with the first integrity level. For example, assume that datarecorded with verify has the first integrity level, as shown in FIG. 10.Such data with verify has high integrity after recording but requires along recording time. The data recorded with verify includes PC data orthe like. When data is recorded with verify, bit 1 as the integrity flagis recorded in a sector field as the recording destination, and insector fields which form a block to which that sector block belongs.

Conversely, when bit 0 is recorded as the integrity flag in theintegrity flag area, a sector field including this integrity flag isincluded in a block recorded with the second integrity level. Forexample, assume that data recorded without verify and data withoutreplacement have the second integrity level, as shown in FIG. 10. Suchdata recorded without verify and without replacement have low integrityafter recording but require only a short recording time. The datarecorded without verify and without replacement include, e.g., AV dataand the like. When data is recorded without verify or withoutreplacement, bit 0 as the integrity flag is recorded in a sector fieldas the recording destination, and in sector fields which form a block towhich that sector block belongs.

FIG. 11 shows the relationship between the integrity level of data to berecorded and the integrity bit in a block as a recording destination.The relationship between the integrity level of data to be recorded andthe integrity bit in a block as a recording destination will beexplained below with reference to FIG. 11.

A case will be explained below wherein data is recorded by block write,i.e., in units of blocks.

When a host apparatus 3 instructs a disk drive 2 to make block write ina high integrity mode, the disk drive 2 records data in a target blockas a recording destination in the high integrity mode. At this time, bit1 is recorded as the integrity flag in sector fields that form thetarget block as the recording destination.

When the host apparatus 3 instructs the disk drive 2 to make block writein a low integrity mode, the disk drive 2 records data in a target blockas a recording destination in the low integrity mode. At this time, bit0 is recorded as the integrity flag in sector fields that form thetarget block as the recording destination.

A case will be explained below wherein data is recorded byread-modify-write, i.e., in units of sector fields.

In case of read-modify-write, four cases shown in FIGS. 11 are assumed.In the first case, the target block as a recording destination is alow-integrity block, and the recording mode is the high-integrityrecording mode. In the second case, the target block as a recordingdestination is a high-integrity block, and the recording mode is alsothe high-integrity recording mode. In the third case, the target blockas a recording destination is a low-integrity block, and the recordingmode is also the low-integrity recording mode. In the fourth case, thetarget block as a recording destination is a high-integrity block, andthe recording mode is the low-integrity recording mode. Thehigh-integrity block is a block defined by a set of a predeterminednumber of sector fields recorded with bit 1 as the integrity flag.Conversely, the low-integrity block is a block defined by a set of apredetermined number of sector fields recorded with bit 0 as theintegrity flag.

In case of read-modify-write, the disk drive 2 often executes arecording mode different from that which is instructed from the hostapparatus 3 to the disk drive 2, depending on the integrity bit of thetarget block as the recording destination. More specifically, this isthe fourth case.

In the fourth case, the host apparatus 3 instructs the disk drive 2 toexecute the low-integrity recording mode (e.g., write command withoutverify), but the disk drive 2 executes the high-integrity recording mode(e.g., verify is done after write). In this manner, bit 1 is recorded asthe integrity flag in respective sector fields included in a targetblock as a recording destination, and high integrity of data in thattarget block is maintained (the first integrity level is maintained).

In the first case, when the host apparatus 3 instructs the disk drive 2to execute the high-integrity recording mode, the disk drive continuesto execute the high-integrity recording mode. As a result, bit 1 isrecorded as the integrity flag in respective sector fields included in atarget block as a recording destination, and the integrity of data inthis target block is changed (from the first integrity level to thesecond integrity level).

In the second case, when the host apparatus 3 instructs the disk drive 2to execute the high-integrity recording mode, the disk drive continuesto execute the high-integrity recording mode. As a result, bit 1 isrecorded as the integrity flag in respective sector fields included in atarget block as a recording destination, and high integrity of data inthat target block is maintained (the first integrity level ismaintained).

In the third case, when the host apparatus 3 instructs the disk drive 2to execute the low-integrity recording mode, the disk drive continues toexecute the low-integrity recording mode. As a result, bit 0 is recordedas the integrity flag in respective sector fields included in a targetblock as a recording destination, and low integrity of data in thattarget block is maintained (the second integrity level is maintained).

Whether data recorded in a given sector field has high or low integritycan be determined by looking up the integrity flag in that sector field.This integrity flag can be independently read out since it is includedin the data ID, even when error correction using the ECC1 and ECC2 isdisabled. Furthermore, since the integrity flag is included in the dataID, data integrity can be checked by the IED.

When a certain block is read out, it is indispensable to make errorcorrection using an error correction code in that block. In other words,a block which cannot undergo error correction cannot be read out.However, as described above, the integrity flag can be independentlyread out from a block. That is, even from a block that cannot be readout, integrity bits recorded in sector fields which form this block canbe read out. Whether even a block that cannot be read out is high- orlow-integrity block can be determined by reading out the integrity flagsrecorded in the sector fields of the block that cannot be read out.

In the first and third cases, when the target block as the recordingdestination cannot be read out, target data is recorded in a targetsector field included in the target block as the recording destination,and dummy data is recorded in other sector fields to re-generate ECCblock data, thus executing recording. That is, even when a low-integrityblock cannot be read out, read-modify-write can be made.

In the second and fourth cases, when a target block as a recordingdestination cannot be read out, a system error occurs.

A schematic arrangement of an optical disk recording/reproduction systemthat records various data on the aforementioned DVD-RAM and reproducesvarious data recorded on the DVD-RAM will be explained below withreference to FIG. 6. Various data include the aforementioned integrityflag, dummy data, and the like. The optical disk recording/reproductionsystem to be described below records the integrity flag and dummy dataon the optical disk, and reproduces the integrity flag recorded on theoptical disk, as described above.

As shown in FIG. 6, the optical disk recording/reproduction systemcomprises a disk drive 2 and host apparatus 3. The disk drive 2 includesa controller 21, motor 22, optical head 23, and signal processor 24.

A recording process in which the disk drive 2 records data supplied fromthe host apparatus 3 on the optical disk 1 will be explained first. Datarecording is executed based on a write command sent from the hostapparatus 3. This write command will be described later. The motor 22rotates the optical disk 1 at a predetermined speed under the control ofthe controller 21. Data supplied from the host apparatus 3 to follow thewrite command is supplied to the signal processor 24. The signalprocessor 24 modulates data sent from the host apparatus 3 to generaterecording data. The optical head 23 includes a semiconductor laser (notshown), which emits a recording laser beam that reflects the recordingdata. The optical head 23 undergoes tracking control and focus controlby the controller 21. The recording laser beam emitted by thesemiconductor laser is focused at a predetermined position on theoptical disk 1. As a result, the recording data is recorded at thepredetermined position on the optical disk 1.

A reproduction process in which the disk drive 2 reproduces datarecorded on the optical disk 1 and outputs the reproduction data to thehost apparatus 3 will be explained below. The motor 22 rotates theoptical disk 1 at a predetermined speed under the control of thecontroller 21. The semiconductor laser included in the optical head 23emits a reproduction laser beam. Also, the optical head 23 undergoestracking control and focus control by the controller 21. As a result,the reproduction laser beam emitted by the semiconductor laser isfocused at a predetermined position on the optical disk 1. Reflectedlight of the reproduction laser beam focused on the optical diskreflects data recorded on the optical disk. The reflected light isdetected by a photodetector (not shown) included in the optical head 23.The detection result of the reflected light detected by thephotodetector is supplied to the signal processor 24 as a reflectedlight detection signal. The signal processor 24 generates data recordedon the optical disk 1 on the basis of the reflected light detectionsignal. Furthermore, the signal processor 24 demodulates the generateddata to generate reproduction data, and outputs the reproduction data tothe host apparatus 3.

Recording of PC and AV data will be described with reference to FIG. 7

Recording of AV data and that of normal data (e.g., PC data) aredistinguished by an interface command sent from the host apparatus 3.That is, when the host apparatus 3 sends write command A (PC datarecording command), the disk drive 2 (the optical head 23 of the diskdrive 2) records bit 1 (first identification information) as theintegrity flag in the integrity flag area of a sector field as arecording destination upon data recording. At this time, bit 1 isrecorded as the integrity flag not only in the sector field as therecording destination but also in all sector fields included in an ECCblock which includes the sector field as the recording destination. Thatis, write command A instructs the high-integrity recording mode.

When the host apparatus 3 sends write command B (AV data recordingcommand), the disk drive 2 (the optical head 23 of the disk drive 2)records bit 0 (second identification information) as the integrity flagin the integrity flag area of a sector field as a recording destinationupon data recording. At this time, bit 0 is recorded as the integrityflag not only in the sector field as the recording destination but alsoin all sector fields included in an ECC block which includes the sectorfield as the recording destination. That is, write command B instructsthe low-integrity recording mode.

FIG. 8 is a flow chart showing recording of the integrity flag based onthe write command.

Upon recording data with the first integrity level on the optical disk,the host apparatus 3 issues write command A. The disk drive 2 receivesthis write command A (YES in ST11), and bit 1 is recorded as theintegrity flag in the integrity flag area of a sector field as arecording destination (ST14). After that, actual recording starts(ST13).

On the other hand, upon recording data with the second integrity levelon the optical disk, the host apparatus 3 issues write command B. Uponreceiving write command B (NO in ST11), the disk drive 2 records bit 0as the integrity flag in the integrity flag area of a sector field as arecording destination (ST12). After that, actual recording starts(ST13).

FIG. 9 is a flow chart showing details of recording in the flow chartshown in FIG. 8, and especially, recording of data which is smaller thanan ECC block size.

An ECC block including a target sector field as a recording destinationis read (ST21). If this ECC block is read normally (YES in ST22), targetdata patches a portion of the read ECC block data, which corresponds tothe target sector field, and the ECC block is re-arranged and recordedin the original ECC block (ST23). If no abnormality is found inrecording (NO in ST24), this means completion of read-modify-write.After that, if verify is required (YES in ST25), verify starts.

In verify, the recorded data is checked (ST29). If it is confirmed thatthe data is recorded normally (YES in ST30), a series of recordingoperations normally terminate. If it is not confirmed that the data isrecorded normally (NO in ST30), recording repeats itself a predeterminednumber of retrial times (ST31, ST33). As a result of the retriedrecording, if it is confirmed that the data is recorded normally (YES inST30), a series of recording operations normally terminate. If it is notconfirmed even after the retried recording that the data is recordednormally (NO in ST30, YES in ST31), the control starts a replacementprocess (ST32). That is, recording using a spare area set in advance onthe disk as a recording destination is executed under the control of thecontroller 21 of the disk drive 2.

If any abnormality is found upon recording in step ST23 (YES in ST24),recording repeats itself a predetermined number of retrial times (ST26,ST27). If any abnormality is found in recording even after the recordingis retried a predetermined number of times (YES in ST27), the controlstarts a replacement process (ST28). That is, recording using a sparearea set in advance on the disk as a recording destination is executedunder the control of the controller 21 of the disk drive 2.

Upon reading an ECC block that includes the target sector field as therecording destination (ST21), if this ECC block cannot be read normally(NO in ST22), that is, if error correction cannot be made using the ECCincluded in this ECC block, a retrial is made a predetermined number oftimes. If the ECC block cannot be read normally even after retrials (YESin ST34), the integrity flag of the integrity flag area of the recordingdestination is reproduced (ST35). This integrity flag is included in thedata ID, and can be independently read out even when error correctionusing the ECC1 and ECC2 is disabled. Furthermore, since this integrityflag is included in the data ID, data integrity can be checked by theIED.

If bit 1 is reproduced as the integrity flag, it is determined that datarecorded in the sector field which includes this integrity flag musthave high integrity (NO in ST36). In this case, the control cannot starta replacement process, and this flow terminates abnormally. By contrast,if bit 0 is reproduced as the integrity flag, it is determined that datarecorded in the sector field which includes this integrity flag can havelow integrity (YES in ST36). In this case, the control startsreplacement process # (ST32). That is, recording using a spare area setin advance on the disk as a recording destination is executed under thecontrol of the controller 21 of the disk drive 2.

Replacement process # will be explained below. In this replacementprocess #, desired data is recorded in a target sector included in areplacement block, and dummy data is recorded in sectors other than thetarget sector included in the replacement block. The dummy data is, forexample, partially corrected data or padding data of 0b for all bits.

A process executed when different types of identification informationare reproduced from the integrity flag areas of a predetermined numberof sector fields that belong to an identical ECC block will be explainedbelow. Normally, an identical integrity flag is recorded in theintegrity flag areas of a predetermined number of sector fields thatbelong to an identical ECC block. However, the flag cannot often benormally read out due to some factors, and different identificationflags may be reproduced from the integrity flag areas of a predeterminednumber of sector fields that belong to an identical ECC block.

In such case, the signal processor 24 of the disk drive 2 checks thelikelihood of identification flags. The likelihood is determined bymajority. That is, a type corresponding to the larger number of readoutidentification flags of those read out from the integrity flag areas ofa predetermined number of sector fields that belong to an identical ECCblock is determined to be a correct identification flag.

The effects of the present invention will be summarized below.

Conventionally, when PC data is overwritten on AV data, the error rateincreases upon read-modify-write due to the absence of defectmanagement. That is, ECC block data cannot be read out uponread-modify-write, that ECC block consequently cannot undergo areplacement process, and read-modify-write terminates abnormally.

In the present invention, in order to solve such problem, anidentification information area which can be independently reproducedirrespective of error correction using an error correction code isassured on each sector field on the disk. This identificationinformation area stores one of first identification information whichindicates that data is recorded with a first integrity level, and secondidentification information which indicates that data is recorded with asecond integrity level lower than the first integrity level.

In this way, even when an ECC block cannot be normally reproduced uponread-modify-write, if only this identification area can be reproduced,at least whether the recorded data has the first integrity level(high-integrity data) or second integrity level (low-integrity data) canbe detected. If it is determined that the recorded data is data with thesecond integrity level, this ECC block is replaced by a replacementblock in a spare area assured in advance on the disk, thus solving theaforementioned problem in read-modify-write.

According to the present invention, the following information recordingmedium, information recording apparatus, information recording method,information reproduction apparatus, and information reproduction methodare provided:

(1) an information recording medium which can reduce the error rate uponread-modify-write when data is overwritten in units of sector fields ondata recorded in units of ECC block data;

(2) an information recording apparatus and method which can reduce theerror rate upon read-modify-write when data is overwritten in units ofsector fields on data recorded in units of ECC block data; and

(3) an information reproduction apparatus and method which can reducethe error rate upon read-modify-write when data is overwritten in unitsof sector fields on data recorded in units of ECC block data.

Additional advantages and modifications will readily occur to thoseskilled in the art. Therefore, the invention in its broader aspects isnot limited to the specific details and representative embodiments shownand described herein. Accordingly, various modifications may be madewithout departing from the spirit or scope of the general inventiveconcept as defined by the appended claims and their equivalents.

What is claimed is:
 1. An information recording medium which has aplurality of sector fields that record data, and in which a block isdefined by a set of a predetermined number of sector fields, whereineach sector field has an identification information area for storing oneof first identification information indicating that data is recordedwith a first integrity level, and second identification informationindicating that data is recorded with a second integrity level lowerthan the first integrity level.
 2. A medium according to claim 1,wherein the identification information areas of sector fields includedin one block consistently store one of the first identificationinformation and second identification information.
 3. A medium accordingto claim 1, wherein the identification information area can beindependently reproduced irrespective of an error correction processusing an error correction code included in ECC block data recorded inthe block.
 4. A medium according to claim 1, wherein the sector fieldincludes a recording field which records user data, and a header fieldwhich records address data, the recording field includes theidentification information area, when ECC block data is recorded in theblock, a predetermined number of sector data generated based on the ECCblock data are recorded in a predetermined number of recording fieldsincluded in the block to have one-to-one correspondence therebetween,the ECC block data includes block data, a first error correction code,and a second error correction code, the block data includespredetermined data which are arranged along a first direction and asecond direction perpendicular to the first direction, the first errorcorrection code corrects the predetermined data arranged along the firstdirection, the second error correction code corrects the predetermineddata arranged along the second direction, the sector data includes apart of the block data broken up into the predetermined number of data,a part of the first error correction code corresponding to the part ofthe block data, and a part of the second error correction code broken upinto the predetermined number of data, and the identificationinformation area can be independently reproduced irrespective of anerror correction process using the first and second error correctioncodes.
 5. An information recording apparatus for recording informationon an information recording medium which has a plurality of sectorfields that record data and respectively have identification informationareas, and in which a block is defined by a set of a predeterminednumber of sector fields, comprising: recording means for recording, inthe identification information area, first identification informationindicating that data is recorded with a first integrity level whendesired information is recorded with the first integrity level on saidinformation recording medium, and recording, in the identificationinformation area, second identification information indicating that datais recorded with a second integrity level when desired information isrecorded with the second integrity level on said information recordingmedium.
 6. An apparatus according to claim 5, further comprisingrecording means for, when desired information is recorded with the firstintegrity level in a predetermined block, consistently recording, in theidentification information areas of sector fields included in thepredetermined block, the first identification information indicatingthat data is recorded with the first integrity level, and for, whendesired information is recorded with the second integrity level in apredetermined block, consistently recording, in the identificationinformation areas of sector fields included in the predetermined block,the second identification information indicating that data is recordedwith the second integrity level.
 7. An apparatus according to claim 6,further comprising recording means for, when desired information is tobe recorded in a predetermined sector field included in a predeterminedblock with the first or second integrity level, determining one of thefirst and second integrity levels as an integrity level of actualrecording on the basis of the relationship between the integrity levelof the information to be recorded, and the integrity level indicated byidentification information reproduced from the identificationinformation areas of sector fields included in the predetermined blockas a recording destination, consistently recording the firstidentification information in the identification information areas ofthe sector fields included in the predetermined block when the integritylevel of actual recording is determined to be the first integrity level,and consistently recording the second identification information in theidentification information areas of the sector fields included in thepredetermined block when the integrity level of actual recording isdetermined to be the second integrity level.
 8. An apparatus accordingto claim 6, further comprising: first sector-unit recording means for,when a predetermined block can undergo error correction using an errorcorrection code included therein, and desired information is to berecorded in a predetermined sector field included in the predeterminedblock with the first or second integrity level, determining one of thefirst and second integrity levels as an integrity level of actualrecording on the basis of the relationship between the integrity levelof the information to be recorded, and the integrity level indicated byidentification information reproduced from the identificationinformation areas of sector fields included in the predetermined blockas a recording destination, consistently recording the firstidentification information in the identification information areas ofthe sector fields included in the predetermined block when the integritylevel of actual recording is determined to be the first integrity level,and consistently recording the second identification information in theidentification information areas of the sector fields included in thepredetermined block when the integrity level of actual recording isdetermined to be the second integrity level; second sector-unitrecording means for, when a predetermined block cannot undergo errorcorrection using an error correction code included therein, the secondidentification information is reproduced from the identificationinformation areas of sector fields included in the predetermined block,and desired information is to be recorded in a predetermined sectorfield included in the predetermined block with the first integritylevel, consistently recording the first identification information inthe identification information areas of the sector fields included inthe predetermined block, recording the desired information in thepredetermined sector field included in the predetermined block, andrecording dummy information in the sector fields other than thepredetermined sector field included in the predetermined block; andthird sector-unit recording means for, when a predetermined block cannotundergo error correction using an error correction code includedtherein, the second identification information is reproduced from theidentification information areas of sector fields included in thepredetermined block, and desired information is to be recorded in apredetermined sector field included in the predetermined block with thesecond integrity level, consistently recording the second identificationinformation in the identification information areas of the sector fieldsincluded in the predetermined block, recording the desired informationin the predetermined sector field included in the predetermined block,and recording dummy information in the sector fields other than thepredetermined sector field included in the predetermined block.
 9. Anapparatus according to claim 8, wherein the dummy information ispartially corrected data or padding data of 0b for all bits.
 10. Anapparatus according to claim 6, further comprising determination meansfor, when different kinds of identification information are reproducedfrom the identification information areas of a predetermined number ofsector fields which belong to an identical block, determining likelihoodfrom those pieces of identification information.
 11. An informationrecording method comprising: the step of, when desired information isrecorded with a first integrity level in an information recording mediumwhich has a plurality of sector fields that record data and respectivelyhave identification information areas, and in which a block is definedby a set of a predetermined number of sector fields, recording data ineach identification information area with the first integrity level; andthe step of, when desired information is recorded with a secondintegrity level in the information recording medium, recording data ineach identification information area with the second integrity level.12. A method according to claim 11, further comprising the steps of: thestep of, when desired information is recorded with the first integritylevel in a predetermined block of the information recording medium,consistently recording data in the identification information areas ofsector fields included in the predetermined block with the firstintegrity level; and the step of, when desired information is recordedwith the second integrity level in a predetermined block of theinformation recording medium, consistently recording data in theidentification information areas of sector fields included in thepredetermined block with the second integrity level.
 13. A methodaccording to claim 12, further comprising: the step of, when desiredinformation is to be recorded in a predetermined sector field includedin a predetermined block with the first or second integrity level,determining one of the first and second integrity levels as an integritylevel of actual recording on the basis of the relationship between theintegrity level of the information to be recorded, and the integritylevel indicated by identification information reproduced from theidentification information areas of sector fields included in thepredetermined block as a recording destination, consistently recordingthe first identification information in the identification informationareas of the sector fields included in the predetermined block when theintegrity level of actual recording is determined to be the firstintegrity level, and consistently recording the second identificationinformation in the identification information areas of the sector fieldsincluded in the predetermined block when the integrity level of actualrecording is determined to be the second integrity level.
 14. A methodaccording to claim 12, further comprising: the step of, when apredetermined block can undergo error correction using an errorcorrection code included therein, and desired information is to berecorded in a predetermined sector field included in the predeterminedblock with the first or second integrity level, determining one of thefirst and second integrity levels as an integrity level of actualrecording on the basis of the relationship between the integrity levelof the information to be recorded, and the integrity level indicated byidentification information reproduced from the identificationinformation areas of sector fields included in the predetermined blockas a recording destination, consistently recording the firstidentification information in the identification information areas ofthe sector fields included in the predetermined block when the integritylevel of actual recording is determined to be the first integrity level,and consistently recording the second identification information in theidentification information areas of the sector fields included in thepredetermined block when the integrity level of actual recording isdetermined to be the second integrity level; the step of, when apredetermined block cannot undergo error correction using an errorcorrection code included therein, the second identification informationis reproduced from the identification information areas of sector fieldsincluded in the predetermined block, and desired information is to berecorded in a predetermined sector field included in the predeterminedblock with the first integrity level, consistently recording the firstidentification information in the identification information areas ofthe sector fields included in the predetermined block, recording thedesired information in the predetermined sector field included in thepredetermined block, and recording dummy in formation in the sectorfields other than the predetermined sector field included in thepredetermined block; and the step of, when a predetermined block cannotundergo error correction using an error correction code includedtherein, the second identification information is reproduced from theidentification information areas of sector fields included in thepredetermined block, and desired information is to be recorded in apredetermined sector field included in the predetermined block with thesecond integrity level, consistently recording the second identificationinformation in the identification information areas of the sector fieldsincluded in the predetermined block, recording the desired informationin the predetermined sector field included in the predetermined block,and recording dummy information in the sector fields other than thepredetermined sector field included in the predetermined block.
 15. Amethod according to claim 14, wherein the dummy information is partiallycorrected data or padding data of 0b for all bits.
 16. A methodaccording to claim 12, further comprising the step of, when differentkinds of identification information are reproduced from theidentification information areas of a predetermined number of sectorfields which belong to an identical block, determining likelihood fromthose pieces of identification information.
 17. An informationreproduction apparatus for reproducing information from an informationrecording medium which has a plurality of sector fields that recorddata, and in which each sector field has an identification informationarea that records one of first identification information indicatingthat data is recorded with a first integrity level, and secondidentification information indicating that data is recorded with asecond integrity level lower than the first integrity level, and a blockis defined by a set of a predetermined number of sector fields,comprising: reproduction means for acquiring information that pertainsto integrity by reproducing the first identification information orsecond identification information from the identification informationarea.
 18. An information reproduction method for reproducing informationfrom an information recording medium which has a plurality of sectorfields that record data, and in which each sector field has anidentification information area that records one of first identificationinformation indicating that data is recorded with a first integritylevel, and second identification information indicating that data isrecorded with a second integrity level lower than the first integritylevel, and a block is defined by a set of a predetermined number ofsector fields, comprising: the step of acquiring information thatpertains to integrity by reproducing the first identificationinformation or second identification information from the identificationinformation area.